I doubt there are as many stamp collectors who hate collecting stamps as there are writers who hate writing. And I would say the same of largely vocational activity. I say “vocational” because I have absolutely no time for the proponents of “professionalism” in writing. For ninety-nine percent of those who take to the page (for any reason) writing will be a vocation. Perhaps some money will be done as part of this vocation — much like the stamp collector who offloads certain expensive stamps here and there. But if money is the main reason for writing, well there are much better and faster ways of getting rich. Unless you are already rich, in which case writing is a perfect money laundering scheme.
The hate of many, I think, is born of the frustrations of participating in an industry in which success is hardly ever attained and even if attained means very little. In other words, there are too many people writing who do it because they want to see their name on a book cover, not because they love or need to write. Books have been idealised and romanticised for as long as they have existed and we have all at one point fantasised about taking a romantic interest or family member to a bookshop, to show them our name on a book on the shelf — clap, clap, how brilliant.